1. Rhubarb
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2. Recap In the last class we learnt about
Aloe contains dried juice obtained by
Making incisions of the leave bases of
Various species of Aloe.
Belongs to the Family Liliaceae
Contains Anthraquinone glycosides
Used as strong purgative. PH

3. Objectives On completion of this lesson, you would be able to know:
The monograph of Rhubarb
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4. Rhubarb Synonym : Rheum, Rhizome-Rhei Rhubarb - Rhizome
Biological Source : Peeled and dried roots and
rhizomes of
Rheum palmatum
Rheum officinale
Rheum emodi
Rheum webbianum
Family : Polygonaceae
Fig.14.1
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5. China, Tibet, Germany, India and other European
Rhubarb
Geographical Source :
China, Tibet, Germany, India and other European
Countries
In India Kulu and Kulaman
Kashmir
Sikkim
Assam
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6. Rhubarb Organoleptic characters: Colour : Brown to yellow
Odour : Fragrant
Taste : Bitter and Astrigent
Size : 2 to 20 cm in length and
1.5 to 2 cm in diameter
Shape : Sub-cylindrical, barrel-shaped,
conical or in planoconvex pieces.
Fig.14.2
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7. Rhubarb Chemical Constituents :
Contains Anthraquinone derivatives and their salts.
Chrysophanol Aloe-emodin
Rein Physicon
Gallic acid Rhein acids
Starch and Calcium oxalate
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8. Rhubarb Chemical tests : 1. With Ammonia, it acquires Pink colour.
2. With 5% Potassium hydroxide it gives Blood Red colour.
3. Under UV-radiation Rheum emodi gives Brown colour.
4. Borntrager’s test for Anthraquinone is positive with Rhubarb.
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9. Rhubarb Uses : Mild purgative Astringent
In small doses it acts as Stomachic in Diarrhoea of children.
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10. Summary In this class we learnt about
Rhubarb consists of peeled dried roots and rhizomes of
Rheum palmatum, R. officinale, R. emodi and
R.webbianum (Indian species) is belongs to the
Family Polygonaceae
Contains Anthraquinone derivatives as main chemical constituents
Used as mild purgative.
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11. Quiz 1. Rhubarb belongs to the family Polygonaceae Leguminosae
Solanaceae
Umbelliferae
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12. Quiz 2. Rhubarb is used as Antipyretic Carminative Mild purgative
Anti-viral
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13. Quiz Rhubarb contains Alkaloids Glycosides Volatile oils Carbohydrates
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14. Frequently Asked Questions
Give two examples for Laxatives. (Mar/Apr’2005)
Mention the Biological Source, Active Chemical
Constituents and Uses of Rhubarb. (September’2002)
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